Circuit Description

PCM requires an accurate indication of fuel level for EVAP system diagnosis. Fuel level in fuel tank changes the rate of vacuum decay/change for EVAP system leak DTCs. Fuel level sensor changes resistance based on fuel level.

The IPC applies a voltage (about 12 volts) on signal circuit to sensor. IPC monitors changes in this voltage caused by changes in resistance of sensor to determine fuel level. When fuel tank is full, sensor signal voltage is high and vice-versa. This input is used to calculate fuel level in fuel tank.

DTC will set when PCM senses the fuel level signal voltage has not changed and vehicle has been operating for a specific amount of time.